The placenta protein, SP1 is an oncoplacental protein: it is produced in the placenta and in certain tumors. It is present in the serum and urine of pregnant women and in the serum of patients with trophoblastic tumors. Evidence exists for the production of SP1 in tumors other than trophoblastic. We intend to study the basic molecular characteristics of SP1 and the expression of SP1 in the normal state and in malignant diseases: what types of tumors produce SP1, what are the levels of SP1 in the serum and urine or tumor patients, and what are the normal levels of SP1. Quantitation of SP1 is done by radioimmunoassay. An enzyme-linked immunosorbent assay (ELISA) will be developed for SP1. Increased sensitivity is achieved by using a fluorigenic enzyme substrate instead of a colorigenic. For possible future specific immunotherapy of SP1 producing tumors, a nonprimate animal model is necessary. We will attempt to identify SP1 in laboratory animals by immunological techniques.